The moon is made up mostly of _______, similar to minerals on earth

A racing car is travelling at 70 m/s and accelerates at -14 m/s2. What would the car’s speed be after 3 s?

Leno4ka [110]

<h3><u>Question</u><u>:</u></h3>

A racing car is travelling at 70 m/s and accelerates at -14 m/s^2. What would the car’s speed be after 3 s?

<h3><u>Statement:</u></h3>

A racing car is travelling at 70 m/s and accelerates at -14 m/s^2.

<h3><u>Solution</u><u>:</u></h3>

Initial velocity (u) = 70 m/s
Acceleration (a) = -14 m/s^2
Time (t) = 3 s
Let the velocity of the car after 3 s be v m/s
By using the formula,

v = u + at, we have

$v = 70 + ( - 14)(3) \\ = > v = 70 - 42 \\ = > v = 28$

So, the velocity of the car after 3 s is 28 m/s.

<h3><u>Answer:</u></h3>

The car's speed after 3 s is 28 m/s.

Hope it helps

3 0

3 years ago

A crate is lifted vertically 1.5 m and then held at rest. The crate has weight 100 N (i.e., it is supported by an upward force o

Rainbow [258]

Answer:

5..No work is being done.

Explanation:

Hello!

Remember that the concept of work is defined as the force required to move a certain body distance, it is calculated as the product of force by distance.

therefore, the work required to raise the box is 150J.

However, the work required to keep the box lifted without moving is zero since although the box has a force due to the weight it does not move.

6 0

3 years ago

Relativistic kinetic energy is conserved in all reference frames. True O False

Free_Kalibri [48]

Answer:

i think it is true

Explanation:

7 0

3 years ago

Scientists want to place a 3400.0 kg satellite in orbit around Mars. They plan to have the satellite orbit at a speed of 2480.0

BaLLatris [955]

Answer:

Part a)

$r = 6.96 \times 10^6 m$

Part b)

$F_g = 3.004 \times 10^3 N$

Part c)

$a = 0.88 m/s^2$

Part d)

$v = \frac{2480}{2} = 1240 m/s$

Explanation:

Part a)

As we know that the orbital speed of the satellite is given as

$v = 2480 m/s$

now we will have

$v = \sqrt{\frac{GM_{mars}}{r}}$

now we have

$M_{mars} = 6.4191 \times 10^{23} kg$

$R_{mars} = 3.397 \times 10^6 m$

now we have

$2480 = \sqrt{\frac{(6.67 \times 10^{-11})(6.4191 \times 10^{23})}{r}}$

$r = 6.96 \times 10^6 m$

Part b)

Here force between mars and satellite is the gravitational attraction force which is given as

$F_g = \frac{GM_{mars} m}{r^2}$

$F_g = \frac{(6.67\times 10^{-11})(6.4191 \times 10^{23})(3400)}{(6.96\times 10^6)^2}$

$F_g = 3.004 \times 10^3 N$

Part c)

Acceleration of satellite is the ratio of gravitational force and mass of the satellite

$a = \frac{F_g}{m}$

$a = \frac{3004}{3400}$

$a = 0.88 m/s^2$

Part d)

As we know by III law of kepler

$\frac{T_1^2}{T_2^2} = \frac{r_1^3}{r_2^3}$

here we know that T2 = 8 T1

$(\frac{1}{8})^2= \frac{r_1^3}{r_2^3}$

$\frac{r_1}{r_2} = (\frac{1}{2})^2$

so we have

$r_2 = 4r_1$

as we know that speed is given as

$v = \sqrt{\frac{GM}{r}}$

so we can say since radius is orbit becomes 4 times so the orbital speed must be half

$v = \frac{2480}{2} = 1240 m/s$

7 0

4 years ago

A golf ball has a mass of 120g. Calculate its increase in mass when it is travelling at 40ms1. What is this as a percentage of i

kicyunya [14]

Answer:

$Percentage=8.889\times 10^{-13}$ %

Explanation:

From special theory of relativity the dynamic mass m is related with the rest mass $m_{0}$ of the body as

$m=\frac{m_{0} }{\sqrt{1-\frac{v^{2} }{c^{2} } } }$

Here, c is the speed of light and v is the velocity of object.

Given mass of the golf ball is 120 g.

$m=\frac{120 }{\sqrt{1-\frac{(40)^{2} }{(3\times 10^{8} )^{2} } } }\\m=120(1-\frac{(40)^{2} }{(3\times 10^{8}) ^{2} })^{-\frac{1}{2} } \\$

Now applying the binomial theorem and solve the above equation.

$m=(1+\frac{1}{2}(\frac{40}{3\times 10^{8} }) ^{2} )\\m=120(1+8.889\times 10^{-15})$

Therefore, increase in mass is,

$\Delta m=120\times 8.889\times 10^{-15} \\\Delta m=10.6668\times 10^{-13} g$

Now percentage of increase in mass with rest mass is,

$Percentage=\frac{10.6668\times 10^{-13} g}{120g} \times 100\\Percentage=8.889\times 10^{-13}$

Therefore, the percentage of increase in mass with rest mass is $Percentage=8.889\times 10^{-13}$ .

4 0

4 years ago